Australian National Low Emissions Coal Research and Development Project: Environmental Impacts of Amine-based CO2 Post Combustion Capture (PCC) Process Activity 3: Process Modelling for Amine-based Post- Combustion Capture Plant Deliverable 3.2 Progress Report Revision Description Issue Date 01 Draft January 2012 02 Revision April 2012 03 Revision 2 June 2012 Prepared by CSIRO – Advanced Coal Technology Portfolio This page is intentionally left blank Project Team Do Thong Narendra Dave Paul Feron Merched Azzi Enquiries Merched Azzi CSIRO Energy Technology +61 2 94905307 [email protected] Copyright and Disclaimer © 2012 CSIRO To the extent permitted by law, all rights are reserved and no part of this publication covered by copyright may be reproduced or copied in any form or by any means except with the written permission of CSIRO. Important Disclaimer CSIRO advises that the information contained in this publication comprises general statements based on scientific research. The reader is advised and needs to be aware that such information may be incomplete or unable to be used in any specific situation. No reliance or actions must therefore be made on that information without seeking prior expert professional, scientific and technical advice. To the extent permitted by law, CSIRO (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this publication (in part or in whole) and any information or material contained in it. ACKNOWLEDGEMENTS The authors wish to acknowledge financial assistance provided through Australian National Low Emissions Coal Research and Development (ANLEC R&D). ANLEC R&D is supported by Australian Coal Association Low Emissions Technology Limited and the Australian Government through the Clean Energy Initiative. The authors would like to thank Barry Hopper for his constructive and detailed comments that helped improve the report. The authors extend their thanks to the CSIRO Library Services for their combined and extraordinary efforts. CONTENTS ACKNOWLEDGEMENTS ........................................................................................... IV CONTENTS ..................................................................................................................5 EXECUTIVE SUMMARY ..............................................................................................6 1. PROJECT OBJECTIVES AND CURRENT MILESTONE .................................. 10 2. STATE OF KNOWLEDGE ................................................................................. 10 3. MONOETHANOLAMINE (MEA) DEGRADATION - REVIEW ............................ 13 3.1 Oxidative Degradation of MEA ............................................................................... 13 3.2 Thermal Degradation of MEA ................................................................................. 19 4. DEGRADATION OF 2-AMINO-2-METHYL-1-PROPANOL (AMP) - REVIEW ... 23 4.1 Oxidative Degradation of AMP ............................................................................... 24 4.2 Thermal Degradation of AMP ................................................................................. 29 5.2 Thermal Degradation of PZ .................................................................................... 36 6. DEGRADATION OF METHYL-DIETHANOLEAMINE (MDEA) .......................... 41 6.1 Oxidative Degradation of MDEA ............................................................................. 41 6.2 Thermal Degradation of MDEA .............................................................................. 47 7 AMINE BLENDS................................................................................................ 50 7.1 Oxidative and Thermal Degradation of MDEA/MEA Blend .................................... 52 7.2 Oxidative and Thermal Degradation of AMP/PZ Blend .......................................... 53 7.3 Oxidative and Thermal Degradation of MDEA/PZ Blend ....................................... 53 8. EMISSIONS OF DEGRADATION PRODUCTS: ASPEN-PLUS SIMULATIONS56 8.1 Aspen-Plus Simulation Task ................................................................................... 57 8.2 Impact of Wash Tower Performance – MEA Base Case ....................................... 57 8.3 Atmospheric Emissions of AMP/PZ Solvent ........................................................... 64 8.4 Atmospheric Emissions of MDEA/MEA Solvent ..................................................... 74 11. ANTICIP ATED VOLATILE DEGRADATION EMISSIONS ................................ 96 12. RANKING OF SOLVENTS .............................................................................. 102 13. CONCLUSIONS .............................................................................................. 103 14. RECOMMENDATIONS & FUTURE WORK ..................................................... 106 15. REFERENCES ................................................................................................ 108 5 EXECUTIVE SUMMARY The scientific literature concerning the formation of oxidative and thermal degradation products of MEA, MDEA, AMP, PZ and their select blends have been reviewed in this report. Despite high overall activity in this field, the amount of experimental work carried out for fully characterising and quantifying the degradation of amine solvents and the applicability of these findings to an industrial scale amine-based post combustion capture plant in terms of predicting the atmospheric emissions of solvent degradation products has been found to be far less than anticipated beforehand. The wide spread of reported reaction conditions and applied analytical methods make direct comparison of both the laboratory and pilot plant based degradation studies rather difficult. Nevertheless the laboratory studies, pilot plant scale experiments and public domain technical information from various commercial technology vendors on degradation of amino solvents clearly indicates that in an industrial environment of post combustion CO2 capture, these solvents will most certainly undergo both oxidative and thermal degradation. The extent of degradation and the type of degradation products formed are found to depend upon the structure of amine and the process operating conditions. Of these conditions we highlight the concentration of amine, its CO2 loading, absorber reaction temperature, solvent regenerator temperature, content of oxygen, SOX, NOX and particulate matter in flue gas, composition of particulate matter (Fe, Ni, V, P, Cr, CO etc), catalytic effect of the material of construction of plant equipment towards degradation etc. The plant operating practices, such as the process control and how often a solvent is reclaimed, will also decide both the extent of solvent degradation and the type of degradation products formed. In general, potential degradation products of amine solvents (combination of oxidative and thermal degradation) are likely to be one or more of the following: Ammonia, primary amines / alkanolamines, secondary amines / alkanolamines, tertiary amines / alkanolamines, aldehydes (formaldehyde, acetaldehyde), carboxylates, amides, piperazines, piperazinones, oxazolidpnes, nitrosamines, imidazolidones, N,N-distributed ureas and nitramines. Other compounds may be added to the list if the ongoing research has identified any additional product. The exact chemical structure of these degradation products depends upon the chemical structure of parent amine and the degradation reaction pathways it has followed. Whilst there are a number of pilot plant scale CO2 capture campaigns ongoing around the world, there has been so far not even a single study that has attempted to close the material balance around plant where formation of degradation products within the plant and the atmospheric emissions of these products are fully accounted. Nevertheless, these campaigns do confirm the following: a) More degradation products are formed in an industrial plant environment than what various research groups have so far determined in their laboratory studies. b) In an industrial environment, it is the oxidative degradation that is contributing more towards overall solvent degradation than the thermal degradation. c) Vapour phase atmospheric emissions of heat stable salts and thermal degradation products of amines are likely to be minimal to the point of no concern. d) Formation of nitroso compounds in the industrial plant environment is a reality since both Boundary Dam and ITC pilot plants in Canada confirm formation and detection of 6 1,2,3,6-tetrahydro-1-nitrosopyridine during their MEA and MEA/MDEA campaigns. It should be noted that the Boundary Dam pilot plant was originally built by Union Carbide and later refurbished by Fluor Ltd for SaskPower as per the Fluor Econamine technology and it used proprietary corrosion inhibitors for both amine campaigns. Thus, Strazisar et al., 2003, are correct in asserting that they detected nitrosamines in the lean amine solution at Kerr-MCGee/ABB Lumus technology based post combustion CO2 capture plant at Trona, California, and these compounds may have been formed up to 2.91 µmol per mL of solution. It should be noted that the Trona plant also uses proprietary corrosion inhibitors despite the lean amine (MEA) concentration being less than 20% w/w. e) Corrosion inhibitors currently being recommended and perhaps used